Aspirin may foil breast cancer: study

Can a daily painkiller cut a woman's chance of developing breast cancer? Quite probably, says researcher Evan Simpson, whose lifetime of work on preventing the disease recently uncovered what may be a key step in stopping tumour growth.

Professor Simpson, the director of Prince Henry's Medical Research Institute, believes his team has discovered a way to stop the production of a key protein in the breast - that affects the production of oestrogen - while still allowing the protein to be produced areas such as the brain and bone.

The process blocks the creation of a hormone-like substance called prostaglandin E2, which mean less aromatase (an enzyme) and less oestrogen - the hormone that fuels the growth of cancerous tumours.

The discovery may offer a more sophisticated version of the standard post-surgery treatment Tamoxifen, which also blocks oestrogen production but is not usually given to patients for more than five years because its effect diminishes.

Blocking prostaglandins (and thus oestrogen) is also an effect of common painkillers such as aspirin and ibuprofen, which may explain why women taking painkillers develop less breast cancer.

Recent results from a major study in the United States showed women who take aspirin, ibuprofen or other non-steroidal anti-inflammatory drugs twice a week for at least five years, have 21 per cent reduction in the risk of breast cancer. Taking such drugs for 10 years or more gives 28 per cent less risk of breast cancer, compared with those who reported no or minimal use.

The results - part of an analysis of more than 80,000 post-menopausal women aged 50 to 79 - showed ibuprofen cut risk by 49 per cent, and aspirin cut risk by 21 per cent.

"This appears to have possibilities as a valid therapy," said Professor Simpson. "No one has gone out and said 'Take an aspirin or ibuprofen to prevent breast cancer' ... this is pretty recent data, so it hasn't percolated out yet."

A study of more than 40,000 people in Melbourne is expected to look at the painkiller-breast cancer link this year, to see if the data is similar.

Professor Simpson said ibuprofen and aspirin had other effects when taken, which needed to be considered. Further studies were needed, he said.

Professor Simpson said his research - funded by the state government's breast cancer research consortium - could offer a way to prevent breast cancer and treat women after surgery.

"We think we have found such a target, a protein called LRH1." The discovery is being developed with Duke University in the United States, which is screening the protein for factors that might inhibit its action.

"They have a a library of tens of thousands of peptides - a viral library - so they can screen to look for inhibiting compounds." Any new drug would be years away.

Breast cancer is the most frequently diagnosed cancer among Australian women, with about more than 11,000 new cases each year and 2500 deaths, according to Australian Institute of Health and Welfare figures.